Indexed positive displacement rotary motion device

A rotor assembly comprising first and second rotors having first and second center axes that are offset from co-linear, the rotor assembly comprising:

• a) a pair of drive rotors comprising first and second rotors each rotor comprising one or more lobes, the lobes having offset engagement services configured to engage lobe tips of the opposing rotor, the offset engagement surfaces being formed by a reference axis fixed to the center axis of the opposing rotor and rotating the reference axis with respect to the center axis of the offset surface whereas the distance from the reference axis to form the engagement tip of the opposing rotor plus the distance of a prescribed gap distance or interference fit determines the location of the offset surface,
• b) a through shaft passing through the drive rotors, the through shaft having a center portion in part defining a portion of a sphere, the drive rotors each having an interior portion forming a portion of a concave spherical surface operatively configured to engage the center portion of the through shaft,
• c) an indexing system wherein an index offset surface is positioned on the first rotor, an indexer surface mounted to the through shaft where the indexer surface is positioned so as to engage the index offset surface of the first rotor as the first rotor rotates with the through shaft having a center of rotation which is not co-linear as to the center of rotation of the through shaft.